Openings are known to be provided through walls and doors within which windows are provided. For example, in garage doors and exterior doors, a window opening is generally cut or pre-formed through the door where a window is desired. Insertion of a glass window pane into the window openings often involves providing an interior half frame and an exterior half frame which are secured to each side of the door with horizontally extending screws retaining the glass pane for the window between the half frames within the window opening.
Known such systems for securing glass panes in window openings of doors suffer a number of disadvantages including requiring difficult and expensive installation by reason of use of the screws and providing unsightly appearances due to the visibility of heads of the screws.